Fluid flow in a pipe or a channel occurs ubiquitously in domestic or industrial settings. Generally, the carrying capacity of a pipe depends on the diameter of the pipe, friction within the pipe, and other factors. The flow resistance of a pipe increases rapidly when the flow rate increases above onset of turbulent flow. Turbulence induced friction losses can consume significant unnecessary energy costs annually. Typically, flow can be driven by pumps providing a pressure head that overcomes the wall friction or the drag in the flow. For a given flow rate, an increase in pressure head requires an increase in pumping energy, causing a corresponding increase in the cost of operation. Thus, for a given flow rate, a decrease in drag force, resulting in a decrease in pressure head, is a desired operating strategy. Drag reduction for liquid flow in a pipe or channel flow is commonly achieved by adding chemicals such as surfactants or polymers to the liquid. Through the formation of surfactant micelles or polymer chains in the bulk liquid, the frequency of formation and size of the turbulence eddies can be dampened. While the use of chemicals is effective in reducing drag, the chemicals can be costly and environmentally unfriendly. In addition to the flow resistance, a standard conduit also has poor heat transfer properties that limit the thermal energy exchange between the wall of the conduit and the fluid flowing through the conduit.
Current state of the art considers head loss as a function of the condition inside the pipe. Conventional fluid dynamics holds that rough surfaces inside the pipe promotes a layer of non-moving or slow moving liquid near the pipe wall. This, according to conventional science, increases friction losses. The Hazen-Williams equation is instructive. Pressure drop, in the Hazen-Williams equation is inversely related to the smoothness of the pipe. The roughness coefficient C may be set to 150 for a smooth copper pipe, where a rough cast iron pipe may be as low as 80. For a 10-foot length of 4-inch pipe, the head loss for copper may be 0.007 psi while the head loss for the same pipe in rough cast iron would be 0.022 psi.
Conventional science also teaches that when liquid flowing inside a pipe is asked to change direction or velocity, there is a reduction in energy. This reduction can be translated directly into head loss in a given pipe. As such, in pipe used today, great care has been taken to ensure the interior is as smooth as possible. Advanced fluid dynamics methods of modified interior pipe structures, however, presents a novel improvement on conventional pipe design.